Board repairing machine



" April 20, 1954 T. c. MANN ETAL I 2,675,837

BOARD REPAIRING MACHINE Filed Jan. 21, 1950 v 15 Sheets-Sheet 1 [:1 CiNYQNfi w T'teo alov-e nr :Davl d Sazfohuficam RT-ram Ap 20, 1954 I T. c. MANN ET AL BOARD REPAIRING MACHINE l5 Sheets-Sheet 2 Filed Jan. 21, 1950 A M m mum f April 0, 1954 T; c. M ANN ETAL BOARD REPAIRING MACHINE 15 Sheets-Sheet 3 Filed Jan. 21, 1950 April 20, 1954 T. c. MANN ETAL 2,675,837

BOARD REPAIRING MACHINE Filed Jan. 21, 1950 I I 15 Sheets-Sheet 4 April 0, 1954 T. c. MANN ET AL BOARD REPAIRING MACHINE l5 Sheets-Sheet 5 Filed Jan. 21, 1950 I l l I l I l I I I I l III I III II I 1 lLllllllLlll' -l lull I ll] 154A CI April 20, 1954 T. c. MANN ET AL BOARD REPAIRING MACHINE 15 Sheets-Sheet 6 Filed Jan. 21, 1950 F IQH a E 2 3 M w w m I 2 1 i a W 7 wflsflh/ M 4 April 20, 1954 1-, c, MANN ET AL BOARD REPAIRING MACHINE N. z 2M M %%.W. r11. ma *M 4 2 a w .|!|.l w a a M\ j i m. m m m 1 I a w m. K I O d m 9 a 2 H i m m 1% z I z m w e o m w .1." 1 Mr A. iq/2 Ill n. e I\\\\\\\\. g a I: 0 I. 2 Q 1\ IR m: I a

April 1954 T. c. MANN ET AL BOARD REPAIRING MACHINE Filed Jan. 21, 1950 15 sheets-sheet 9 T. C. MANN ET AL BOARD REPAIRING MACHINE April 20, 1954 l5 Sheets-Sheet 10 Filed Jan. 21, 1950 INvarQ-rem-J flxeod-ore. Q. QKQOAK vid. ..QJ'ck-mcfo 4, QM, v1;%..- LM.-w..

Ji-r-renmaY/ Ap 1954 T. c. MANN ET AL BOARD REPAIRING MACHINE l5 Sheets-Sheet 12 Filed Jan. 21, 1950 Ap 20, 1954 T. c. MANN ET 'AL 2,675,837

BOARD REPAIRING MACHINE Filed Jan. 21, 1950 r 15 Sheets-Sheet l3 April 1954 T. c. MANN ET AL BOARD REPAIRING MACHINE.

15 Sheets-Sheet 14 Filed Jan. 21, 1950 aw r5 QM a mm a Mg J Tea 8 m; r. vdwmw is -w 2 April 20, 1954 T. c. MANN ETAL 2,675,837

BOARD REPAIRING MACHINE Filed Jan. 21, 1950 15 Sheets-Sheet l5 @g 57? road 4 fleociov-e QVLQRW.

David 6.6ohncow M iari z Patented Apr. 20, 1954 BOARD REPAIRING MACHINE Theodore 0. Mann, Beloit, Wis., and David E.

Johnson, Rockford, 111., assignors to Ekstrom- Carlson & 00., Rockford, 111., a corporation of Illinois Application January 21, 1950, Serial No. 139,884

This invention relates generally to a machine for repairing a board having a defect .therein such as a knot, a hole, or an indentation by 15 Claims. (01. 144-2) forming a circular plug and inserting the same H into a circular hole bored in the board for the purpose of removing the defect therefrom. The invention has more particular reference to ma chines of the type in which the plug is cut from a piece of plug stock in the form of a board and transferred laterally to a position over the hole in the board to be repaired for insertion in the latter.

The primary object of the present invention is to provide a machine of the above character in which the plug and the hole receiving the same are tapered so that the plug may be wedged in the hole with a tighter fit than has heretofore been possible.

Another object is to provide an automatic machine for cutting the plug and the hole simultaneously and then bringing the two into axial alinement for insertion of the plug in the hole.

A further object is to mount the hole cutter and mechanism for inserting the plug in the hole on an indexable carriage, the indexing motion of which is utilized in a novel manner to transfer the plug into a position to be inserted in the hole.

Still another object is to provide for cutting the plug out of a piece of grained board and inserting the plug in the hole in the board to be repaired with the grain of the latter and. the plug alined.

A more detailed object is to achieve alinement of the grain of the plug and the board by engaging one end face of the plug as the same is being cut so as to retain positive control over the plug during its alinement with the hole.

A further object is to provide for applying glue to the wall of the freshly cut hole and actuating the glue applicator in a novel manner. v

The invention also resides in the novel manner of deriving energy to actuate the plug insertingmechanism and in the novel mechanism for transferring the plug into alinement with the hole. 7 Other objects and advantages of the invention will become apparent from the followingdetailed description taken in connection with .the accompanying drawings, in which:

Figure 1 is a fragmentary front elevation of a board repairing machine embodying the novel features of the present invention.

Fig. 2 is a fragmentary perspective view of a board having a defect therein. jv

Fig. 3 is a view similar to Fig. 2 showing the board repaired.

Figs. 4, 5, and 6 are schematic views showing difierent positions of a plug during its movement from a piece of plug stock to a position in alinement with a hole in a board to be repaired.

Fig. '7 is a fragmentary side elevation of the board repairing machine with a supporting column thereof broken away.

7 Fig. 8 is a plan view.

Fig. 9 is a fragmentary vertical sectional view taken along the line 9-43 of Fig. 1.

. Fig. 10 is a fragmentary vertical section taken along the line 10-10 of Fig. 9.

Fig. 11 is a fragmentary horizontal section taken along the line I l-l l of Fig. 10.

Figs. 12 and 13 are fragmentary sectional views taken along the line l2l2 of Fig. 10 and showing the parts in different positions.

Fig. 14 is a fragmentary vertical section taken along the line I l-I4 of Fig. 11.

Fig. 15 is a fragmentary sectional view taken along the line |5l5 of Fig. 14.

Fig. 16 is a fragmentary sectional view taken along the line l6|6 of Fig. 11.

Fig. 17 is a fragmentary section taken along the line l1-ll of Fig. 16 with one of the parts broken away.

. Fig. 18 is a development of a barrel cam for lowering the plug holding mechanism.

. Fig. 19 is an enlarged view similar to Fig. 9 showing both the plug and hole cutters advanced.

Fig. 20 is a horizontal section taken along the line 2020'of Fig. 19.

Fig. 21 is a fragmentary sectional view taken along the line 2|2I of Fig. 20.

Fig. 22 is a view similar to Fig. 9 with the parts in different positions.

Fig. 23 is a sectional view taken along the line 2323 of Fi 22.

Fig. 24 is an enlarged fragmentary plan view of the glue applicator.

Fig. 24 is a detailed fragmentary plan view of the actuating cam for the glue applicator.

Fig. 25 is a vertical section taken along the line 25-45 of Fig. 24. Y

Fig. 26 is a fragmentary side elevation taken along the line 26-26 of Fig. 1.

Fig. 27 is a sectional view taken along the line 2|21 of Fig. 24.

Figs. 28 to 33 are diagrammatic views showing difierent steps in the operation of the machine.

Fig. 34 is a hydraulic circuit and electric switch diagram of the machine.

For purposes of illustration, the invention is shown in the drawings incorporated in a machine adapted to operate on a board or workpiece 35 having a defect 36 therein, such as a knot, an indentation, or the like (see Fig. 2), and repair the same by enlarging the defect to form a hole 31 (see Fig. 3) having a predetermined internal circular contour into which a correspondingly shaped plug 38 is inserted. While it is contemplated that the hole may be cut in the board in a separate machine, it is preferred to accomplish this in the same machine in which the plug is cut and preferably at the same time so that it is necessary to position the board only once both to cut the hole and position the plug therein. It is to be understood, however, that I do not intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

In the exemplary board repairing machine shown (see Figs. 7 and 19), the defective work piece 35 to be repaired and a piece39 of plug stock from which the plug 38 is made are mounted on supports 40 and 4! toward which cutters 42 and 43 are fed to cut the hole 3'! in the workpiece and simultaneously cut the plug 38 which is received in a holder 44. To enable the plug to be driven into the hole with a wedging action, the periphery 45 of the plug is tapered axially and the hole 31 is formed with a correspondingly tapered side wall 46. Ihe hole cutter is transferred laterally out of the way and, at the same time, the plug holder with the plug therein is transferred laterally to present the plug in alinement with the hole (see Figs. 6 and 22). Because of its taper, the plug is inverted during its ransfer laterally (see Fig. During this transfer, a coating of glue is delivered from a nozzle 47 of a glue applicator 48 to the wall of the hole. Finally, with the plug thus inverted to extend the tapers of the plug and the hole in the same direction axially, a plug pusher 43 (see Figs. 6 and 22) is advanced to press the plug out of the holder and into the hole.

The frame of the machine comprises a post or column 50 (see Figs. '7 and 8) upstanding from a base 5| formed on its top surface as a generally horizontal table which constitutes the work support 40 and against which the defective board 35 is clamped during operations on the board. To permit the hole cutter 42 to advance through the board without hitting the table, the latter is formed with a circular recess 52 (Figs. 19 and 22) over which the defect is positioned when the board is clamped flat against the table.

The hole and plug cutters 42 and G3, the mechanisms for holding the plug 38 and transferring the same to the hole 31, the glue applicator 48, and the plug pusher 49 are in this instance, together with their actuators and the support 4| for the plug stock 33, all mounted on a common support or head 53 which in order to shorten the over-all cycle of the machine is slidable along vertical ways 54 on the column 50 for rapid approach and return movements relative to the table 40. Actuation of the head at this rapid rate is elfected preferably by a hydraulic actuator (see Figs. 9 and 28) comprising a stationary cylinder 55 and a piston 56 therein whose rod is bolted to the head, the cylinder being secured as by brackets 5! to the column.

The motion of the head 53 toward the table 40 is utilized in this instance to clamp the defective board 35 against the table and the motion of the head away from the table is utilized to release the board. For this purpose, two clamping elements 58 and 59 (see Figs. 1 and 10) in the form of plungers are carried by the head and yieldably urged for movement downwardly with respect to the latter and into engagement with the top surface of the board. One plunger 58 is slidable in and guided by a vertically disposed cylinder 60 depending rigidly from the underside of the frame and positioned so that the plunger engages the board on one side of the defect while the other plunger 59 is slidable axially in a similarly mounted cylinder 6| positioned so that the plunger engages the board on the opposite side of the defect. Pins 62 on the cylinders are received in axially extending slots 63 in the plungers to limit movement of the latter downwardly with respect to the cylinders.

Hole cutting mechanism In order to cut the hole 31 with its side wall tapering axially, the hole cutter 42 (see Fig. 19) is formed with radially disposed teeth on its lower end surface and axially tapering teeth on its side surface. The cutter is fast on a spindle 65 (Fig. '9) disposed vertically and journaled in bearings 55 and 66 in a tool carriage or slide 61 which is supported in the head 53 for vertical reciprocating movement toward and away from the table to feed the cutter along the axis of the defect 36 and is adapted to move the cutter laterally across the table 40 and out of alinement with the hole to permit the insertion of the plug 38 into the latter. Herein, the slide is shaped generally as a solid cylinder slidable in and guided by the walls of a vertically disposed hollow cylinder 68 in the head, the walls of the hollow cylinder also providing a bearing so that, with the spindle mounted eccentrically in the slide on an axis parallel to the axis of rotation of the slide, the latter may be rotated to index the hole cutter angular-1y across the table and into and out of alinement with the defect.

In the present instance, the hole cutter slide 61 is reciprocated vertically by a hydraulic actuator. This actuator (see Figs. 10 and 29) comprises a cylinder 69 bolted to and movable with the head 53 and having a piston 70 therein whose r d is secured at its lower end to a yoke H. The latter is slidable in vertical ways 12 (see Figs. 10 and 12) on the head and is formed with a flange 13 which is received in an annular groove it on the outside of the slide adjacent the upper end thereof to couple the yoke and the slide for axial movement together but permittin the slide to rotate with respect to the yoke.

Another hydraulic actuator is employed in the present instance to turn the slide 6'! and index the hole cutter 42 laterally across the table 40. This actuator (see Figs. 10 and 11) comprises a vertically disposed cylinder 15 which is bolted to the head 53 and has a piston 16 therein whose rod is formed intermediate its ends with rack teeth H. The latter mesh with the teeth on a pinion 18 coupled through bevel gears 19 to a spur gear 85 which meshes with anelongated gear 81 keyed to a sleeve 82 secured to the top of the hole cutter slide. Elongating the teeth of the gear 8! enables the latter to remain in mesh with the spur gear while reciprocating with the hole cutter slide.

Rotation of the spindle 64 and the hole cutter 42 thereon is effected herein by an electric motor 83 bolted to the head 53 and coupled through a spur gear 84 to a long-hubbed sleeve gear 85 which is journaled in bearings 86 in the head and fixed against axial movement relative thereto by collars $1. The sleeve gear 85 is coupled to a shaft 99 journaled in the sleeve 82 on'the hole cutter slide 61 and carrying at its lower end a spur gear 89 meshing with a gear 90 fast on the spindle, axial movement of the shaft relative to the sleeve being prevented by collars 9| on theshaft. To permit the shaft 88' and the hole cutter slide to reciprocate vertically with respect to the head While maintaining the driving connections between the motor and the spindle 64, the shaft and the sleeve gear 85 are joined together by means of a spline coupling 92 formed by external spline teeth on the upper end of the shaft andinternal teeth in the gear. The shaft is concentric with the hole cutter slide so that the latter may b rotatedto index the hole cutter without breaking the coupling between th shaft and the spindle.

To enable the hole cutter 42 to yield axially with respect t'o'the slide Bl, the hole cutter spindle 54 is formed by two telescoping pieces 64 and 64* (see Fig. 9), the upper on 64 of which is journaled in the bearings 69 in the slide and fixed against axial movement with respect thereto and the lower one 64* of which is journaled in the bearings 65 carried in a Sleeve 93. The latter is axially slidable in a cylinder 94 in the slide and yieldably urged toward the work by a I spring 95, bearin at its upper end against a shoulder on the slide and at its lower end against the lower spindle part which is axially fixed relative to its bearing sleeve. Rotary motion is transmitted from the upper part of the spindle to the lower part thereof by a spline coupling 96 joining the telescoping parts together. A pin 91 in the holecutter slide engages the opposite ends of a longitudinally extending slot 98 in the axially movable spindle bearing sleeve to determine the extent of axial movement of the latter with respect to the slide.

Plug cutting mechanism As contemplated by the present invention, the plug cutter 43 (see Figs; 4, 14, and 19) is adapted to cut the plug 38 from the piece 39 of plug stock so that the peripheral wall of the plug tapers axially to fit in the correspondingly tapered hole 3'! cut by the hole cutter 42 in the board 35 being repaired. Herein, the piece of plug stock is horizontally disposed and plugs are cut therefrom by a trep-anning type of cut ter with the peripheral wall 45 of the plug tapering upwardly away from the horizontal plane of the defective board 35. The plug cutter is fast on the lower endof a vertically disposed spindle 99 journaled in bearings I99 in a sleeve Iill which is recip'rocable in a vertical cylinder I92 disposed in the head 5-3 and laterally spaced from' the axis of the hole cutter slide 51. Relative axial movement between the plug cutter sleeve I GI and the spindle is prevented by a suitable collar I03 on the latter. The extent of vertical movement of the plug cutter sleeve with respect to the head is determined by a pin I04 and a slot I05 disposed respectively in the sleeve and the head.

Reciprocation of the plug cutter sleeve Illl to feed and return the plug cutter relative to the plug stock is effected herein by a hydraulic actuator. The latter comprises a cylinder I96 secured to-the head 53 and a piston I ll! therein whose rod is bolted to a bracket I68 secured a by bolts, I09 to the top of the sleeve. e 4

To rotate the plug cutter spindle 99, the motor 83 is coupled through the spur gear 84 to a longhubbed sleeve gear II!) the hubs of which are journaled in bearings I II in the head 53 and which is secured by collars Hz against axial movement with respect to the head. A spline coupling II3 formed by internal spline teeth in the sleeve gear and external teeth on the upper portion of the spindle couples the latter and the long-hubbed gear IIll together for rotation while permitting the spindle to reciprocate axially relative to the gear.

The piece 39 of plug stock is properly positioned under the plug cutter spindle 99 and above the table 40 in the plug stock support AI which is secured as by brackets II4 to the lower part of the head. Herein, the plug stock support (see Figs. 9 and 14) is a channel bar receiving the plug stock between two upstanding flanges II5 one of which carries leaf springs I I6 to bear against the plug stock and retain the same frictionally inthe support Positioned below a hole In in the plug stock support and axially alined with the plug cutter spindle 99 is the plug holder M which is horizontally disposed and receives each plug after it is cut from the plug stock by the plug cutter. To facilitate insertion of a freshly cut plug into the holder, the hole cutter spindle is formed with an axial bore II8 to receive the shaft IIB of an axially movable plunger I20 which engages a portion of the plug stock forming one end face of the plug 38 being cut and yieldably urges the plug downwardly beyond the lower end of the plug cutter and into the holder. While the plunger may be actuated in various ways, it is preferred, for the sake of simplicity, to employ a compression spring I2I which bears at one end against a shoulder I22 defining the upper end of an enlarged portion I23 of the bore and at its other end against a collar I24 secured to the plunger shaft II9. Bearings I25 in the lower end of the spindle receive the lower end portion of the plunger shaft and center the same with respect to the plug cutter.

For a purpose to appear later, provision is made to insure that plugs cut by the cutter 43 will be received in the holder 4:3 with the grain of the plugs extending in a direction parallel to the grain of the plug stock. To this end, the plunger IE0 is secured against rotation with respect to the plug cutter and the plug engaging or lower end surface I26 of the plunger is roughened to grip the top surface of each plug frictionally and prevent rotation of the latter with the cutter. Herein this is accomplished by flattening the upper end portion l2! of the plunger shaft II9 (see Figs. 14 and 15) and extending the same upwardly beyond the plug cutter spindle 99 and in between the forked ends 128 of a bracket I29. The latter is secured as by screws I39 to the head 53 with the forked ends of the bracket snugly receiving the upper end portion of the shaft. With this arrangement, the plunger shaft is free to slide axially under the action of the spring I2I within the plug cutter spindle but is secured against rotation relative thereto.

7 Plug transferring mechanism Mechanism is provided to support the plug holder 44 under the plug cutter 63 while the plug 38 is being inserted therein by the plunger I20 and to transfer the holder laterally from the plug cutter to a position in which the plug is axially alined with the hole 31 in the board 35 being repaired. During its transfer laterallyisee Figs. 4, 5,.and 6), the plug is inverted so that the sides thereof which converged upwardly while being cut converge downwardly toward the table 40 when positioned in axial alinement with the hole. In addition, the holder, to enable the same to be inverted, is spaced a substantial distance above the table and is lowered during its lateral transfer so that the plug is spaced only a short distance above the hole 3'! after the transfer is completed and preparatory to inserting the plug into the hole.

The plug holder 44 (see Figs. 19, 20, and 21) is shaped as a generally rectangular box having a circular central hole !3I therein larger than the plug and a plug engaging member I32 yieldably urged radially into the hole from each of the four corners of the holder. Each plug en-.

, gaging member is guided in its radial movement by grooves !33 on the upper and lower surfaces of the holder and a radially extending pin I34 pressed into the member and slidably received in radial holes I35 in the holder. The extent of inward movement of each member is determined by a screw I36 on the holder and a slot I 31 in the upper portion of the member. To facilitate entry of a plug into the holder, inwardly facing plug engaging surfaces I38 of the members diverge upwardly away from each other when the holder is disposed under the plug cutter 43. Shoulders I39- on the members limit the extent of entry of a plug into one side of the holder and prevent the entry of plugs into the holder from the other side thereof.

In the present embodiment of the invention, the plug holder 44 is mounted to transfer the plug 38 therein laterally across the table 49, invert the plug, and lower the same all as an incident to the indexing motion of the hole cutter slide To transfer the plug laterally from the plug stock into alinement with the hole, the holder is mounted on an arm I40 (see Figs. 9 and 16) keyed as at I4I to the lower end of a spindle I42 which is rotatable with the hole cutter slide and journaled in bearings I43 in a sleeve I44 mounted in a vertically disposed cylinder I45 in the head. Upon rotation of the spindle, the holder is swung about the axis thereof and angularly across the table.

Lowering of the plug holder during rotation of the plug holder spindle 542 is effected by the cooperation between a barrel cam :45 (see Figs. 9, 1G and 18) formed as a peripheral groove on an enlargement I4! of the spindle and a follower I48 in the form of a pin projecting rigidly into the groove from the wall of the cylinder 45. With the holder positioned under the plug cutter 43 the follower is positioned on an inclined surface 549 of the cam. Upon rotation of the spindle I42 from this position to swing the holder angularly across the table, the follower moves first along the inclined surface I49 to lower the spindle and the holder, then along a flat horizontal dwell surface I50, and finally, along another inclined surface i5! to lower the holder still further and position the holder a short distance above the hole to be plugged.

To invert the plug holder during rotation of the plug holder spindle I42, a shaft I52 (see Figs. 19, 20,. and 22) on the holder is journaled in the lower end 53 of the arm I49 with a beveled ear I54 fast on its outer end meshing with a nonrotatable beveled gear 555. The latter (see Fig. 16) is keyed to a bracket I55 secured as by bolts I51 to the sleeve I44 which is held against rotation with respect to' the head by a pin I58 projecting rigidly from the wall of the cylinder I45 into an axially extending slot I59 in the plug holder sleeve I44. The arm I40 and the enlarged portion I41 of the spindle I42 hold the sleeve I44 against axial movement relative to the spindle so that the nonrotatable beveled gear E55 is lowered with the rotatable beveled gear I54 to provide continuous meshing of the two gears.

In the present instance, the plug transferring mechanism is actuated as an incident to indexing the hole cutter by coupling the hole cutter slide 6? to the plug holder spindle I42 so that the two rotate together. For this purpose, the spindle (see Figs. 9 and 16) at its upper end is spline coupled as indicated at I68 with the lower end portion of a hollow shaft I SI. The latter carries a spur gear IE2 at its upper end to mesh with the long gear 8I on the hole cutter slide. The hollow shaft is fixed against axial movement relative to the head but is journaled in a bearing his secured to the latter as by bolts I84, relative axial movement between the shaft and the spindle being permitted by the spline coupling joining the two.

Provision is made to insure that the grain of the plug 38 cut by the plug cutter 43 and the grain of the board 35 being repaired are always parallel to each other after the plug has been positioned by the plug transfer mechanism in axial alinement with the hole 37 to be plugged. Such relation of the grain of the plug and the grain of the board is accomplished by utilizing the nonrotating plunger I243 to position each plug in the plug holder as described above so that the grain of the plug is parallel to the grain of the plug stock and by supporting the piece of plug stock and a board being repaired so that the angular relation between the grain of the board and the grain of the stock is correlated with the angle through which the plug holder 44 moves about the spindle I42 in its transfer movement from the plug cutter to a position over the hole to be plugged.

In the present instance, the board 35 being repaired and the piece 39 of plug stock are lat-- erally spaced apart in spaced parallel planes (see Fig. l) with the plug stock disposed in a horizontal plane above the table 48. For simplicity (see Fig. 9), the axes of rotation of the plug cutter spindle $9, the hole cutter slide 611', and the plug holder spindle it?! are parallel and disposed in a vertical plane which is perpendicular to the plug stock and board being repaired. With this arrangement, the plug holder is swung through degrees or a half revolution about the axis of the plug holder spindle 44?. and rotated through a half revolution about the axis of the shaft I52 on the holder when the hole cutter slide {57 is indexed angularly through a half revolution about its axis.

Plug inserting mechanism The plug pusher 49 (see Fig. 9) is in the form of a generally cylindrical block adapted to engage the plug 38 and push the same out of the holder 44 and into the hole 3'! when the plug is positioned in the plug holder in axial alinement with the hole. To enable the pusher to be positioned in axial alignment with thehole as an incident to moving the hole cutter 42 out of alinement with the hole, the pusher is secured to the lower end of a rod I65 which is axially slidable in a vertical cylinder I66 formed in the hole cutter slide 61 and angularly spaced 180 degrees from the hole cutter spindle 64 (see Figs. 12 and 13). With this arrangement, when the hole cutter slide is rotated through a half revolution to move the hole cutter out of alinement with thehole, the plug pusher is" automatically alined axially with the hole.

Herein, a sleeve I61 projecting into the upper end of the cylinder I66 slidably receives the upper portion of the'pusher rod and centers the same in the cylinder while a centering block I08, which is secured as by bolts to the bottom of the sleeve, is apertured to receive and. guide an intermediate portion of the rod. To prevent relative rotation between the rod and the hole cutter slide, a groove I69 (see Figs. 9 and 23) in the centering block receives an axially extending key I10 in the rod.

Energy derived from the downward movement of the hole cutter slide 61 in feeding the hole cutter 42 is utilized to actuate the plug pusher 49 after the latter is indexed to a position in alinement with the plug so that it is unnecessary to providea separate power actuator for the pusher. In this instance,lthe. energy is stored in a spring I1I surrounding the pusher rod I65 and the centering sleeve I61 and hearing at its upper end against a shoulder I12 adjacent the top of the plug pusher cylinder I66 and at its lower end against a collar I13 secured to the rod.. The spring urges the latter downwardly, this movement being limited by engagement of the collar with the top of the centering block I68.

To store energy in the spring I'll during feeding of the hole cutter 42, an L-shaped stop I14 secured as by bolts to the head 53 is positioned to engage a shoulder I15 on the pusher and retain the latter at a predetermined distance above the table 40 during feeding of the cutter so as to urge the rod I65 upwardly with respect to the hole cutter slide 61 and compress the spring. When the slide reaches its lowest position, the closed end I16 of a generally U-shaped latch bar I16 is urged by springs I11 (see Figs. 19 and 23) into a transverse notch I18 in the rod. The latch bar is slidable horizontally'in the centering block I68 with arms I80 of the latch straddling the pusher rod. In the movement of the closed end of the latch bar into the notch the rod is locked in a position in which the spring I1I is compressed and the pusher is retained closely adjacent the bottom of the slide. The rod and the pusher thereon remain locked in this position during retraction and indexing of the slide, a transverse slot I19 in the plug holder sleeve I44 (see Figs. 22 and 32) permitting one of the legs I80 of the U- shaped latch to pass by the plug holder sleeve during such indexing.

Tripping the latch I16 to release the pusher 49 after the latter has been positioned over the hole 31 and axially alined therewith is effected by lowering the hole cutter slide 81 a second time to bring the legs I80 of the latch which are tapered at their ends to constitute follower surfaces into contact with a cam I8I secured to the plug holder sleeve I44. Upon engagement with the cam, the latch is moved transversely of the axis of the rod I65 to release the pusher. Upon suchrelease, the latter is urged under the action of the spring I1I downwardly toward the plug 38 to pushthe same into the hole with a hammer blow action (see Fig. 33) c In the downward movement of the slide, the stop I14 engages a collar I82 (see Fig. 22) fast on the hole cutte r spindle 64 and pushes the latter against the action of the spring 95 to prevent the hole cutter from moving downwardl y into the board being repaired.

'10 Glue applying mechanism After the hole 31'is cut in the board being re' paired and before the plug 38 is inserted in the hole, the wall 46 of the latter is covered with glue dispensed from the glue applicator 48 which is moved into and out of a glue delivering position with respect to the hole wall and which is actuated automatically as an incident to movement of the hole cutter 42 out of alinement with the hole and the plug into alinement therewith. In the present instance, the applicator (see Figs. 23, 24, 25, 26, and 27) comprises a body I83 which is pivoted on a bracket I84 depending from the head and yieldably urged by a spring I85 to swing about a vertical axis in a plane parallel to the table and position the nozzle 41 of the applicator in axial alinement with the bored hole.

To swing the applicator away from the hole 31 when the hole cutter 42 is moved into axial alinement therewith, a. cam I86 (see Figs. 23 and 26) secured to the bottom of the hole cutter slide 61 engages a follower arm I81 upstanding from the body I83 of the applicator and swings the latter about the bracket and against the force ofthe spring I85. When the hole cutter is indexed away from the hole, the body I83 swings'back to position the nozzle 41 over the hole. The applica tor is swung away from the hole to make room for the plug holder 44 and the plug pusher 49 by a cam I88 secured to the holder arm I40 and engaging a follower abutment I89 secured adjustably as by a bolt I90 to the applicator body, the cam disengaging the abutment when the holder is indexed back to the position under the plug cutter.

A port I9I in the applicator body I83 is connected by a flexible hose I92 to a suitable supply of air under pressure and another port I93 in the body is connected by a hose I94 to a suitable glue pot 238. The air port I9I communicates with one end of a cylinder I95 through a passage I96 adapted to be closed by a valve I91 which has an actuator I98 yieldably urged by a spring I99 into a valve closed position. The actuator is in the form of a pin'slidable in the wall of the body and projecting outwardly therefrom. Within the cylinder I95 is a piston 200 which, when air is admitted to the cylinder, is urged against the action of a spring 20I in a direction to close a passage-202 connecting the glue port I93 with the nozzle 41 and to force glue from the passage into the nozzle.

- The nozzle comprises a body 203 having an L-shaped passage with one leg 204 thereof communicating with the passage 202 in the body and another vertically disposed leg 205 terminating in a port 206 from which glue is discharged downwardly. To deflect the glue outwardly, a bolt 201 having a tapered surface 208 on the head thereof is centered within the passage with the head disposed below the port 206 so that the glue is directed first downwardly against the tapered surface and then outwardly against the wall 46.0f the bored hole. Yieldably urged by a spring 209 to close the L-shaped passage and permit glue to be admitted to the nozzle only when the pin I98 is actuated is a piston 2 I 0 having a slot 2| I therein through which the bolt206 is extended.

;..To open the valve I91 and actuate the'glue applicator, the pin I98 constitutes a follower positioned for engagement with the same cam I88 which engages the abutment I89 to move the glue applicator out of the way of the plug holder 44. The engagement between the cam I88 and the pin I98'occurs during the time that the plug 

